Exhaust gas treatment



Nov. 21, 1967" g. {k n uan 3,353,335

EXHAUST GAS TREATMENT I 7 Filed Oct. 19. 1965 INVENTOR. fan A20 401671111560 BY W ATTORNEYS.

Patented Nov. 21, 1%67 3,353,335 EXHAUST GAS TREATMENT Edward A. Caballero, 1216 Spruce Ave, Chico, Calif. 9 926 Filed Oct. 19, 1965, Ser. No. 498,009 8 Claims. (Cl. 5594) ABSTRACT F THE DISCLOSURE An exhaust gas treatment system which includes a horizontal exhaust gas duct, a communicating downwardly sloping exhaust gas duct, first and second recirculation means for dispersing respectively water and a chemical cleaning solution in the horizontal and downwardly sloping ducts respectively, while utilizes a solution of borax, chlorophyll, .and an alkali sulphate detergent in water as the cleaning agent and a method for cleaning exhaust gases is disclosed.

This invention relates to the treatment of exhaust gases from combustion chambers in order to minimize the dispersal of impurities or irritants to the atmosphere.

Attempts are presently being made to control air pollution by reducing the amount of irritants or impurities emitting from the exhaust of a combustion chamber. These attempts have been directed to the additional burning or combustion of exhaust gases in an effort to burn off or chemically alter the nature of impurities. One difficulty with this line of attack is the low efiiciency of the process which is usually on the order of ten to twenty percent. Another difficulty is the high cost inherent in the supply of an additional high temperature area necessary to conduct the combustion operation. Other attempts have been made to reduce air pollution by moving the exhaust gases through a catalytic bed and another form of effort has been to alter the chemical composition of impurities or irritants. Diifioulties with this line of attack reside in the necessity of a high pressure inlet to the catalytic bed which decreases the deficiency of combustion chambers.

It is an object of this invention to reduce the emission of irritants or impurities from an exhaust of a combustion chamber by cleansing them from the exhaust stream.

Another object of this invention is to reduce the emission of irritants from an exhaust stream by cooling the stream and then cleansing irritants therefrom.

A further object of this invention is to treat the exhaust stream of a combustion chamber at temperatures lower than the stream, thus obviating the requirement for additional heat source.

Still another object of this invention is the utilization of a chemical mixture to effect the absorption and cleansing of impurities from an exhaust stream.

A still further object of this invention is to provide a device for reducing the emission of irritants or impurities from an exhaust stream utilizing recirculating liquids.

Still other objects and advantages of the instant invention reside in the combination of elements, arrangements of parts, and features of construction and operation, all as will be more fully pointed out hereinafter and disclosed in the accompanying drawing wherein there is shown a preferred embodiment of this inventive concept.

The drawing is an overall organizational view, partly in section, of the exhaust gas treatment apparatus of the instant invention.

Referring now to the drawing in detail, there is indicated generally at 10 an exhaust gas treatment apparatus of the instant invention connected to the exhaust outlet 12 of a combustion chamber shown generally at 14 which may be a furnace or any other type of exhaust gas pro-ducing device. The major components of exhaust gas treatment apparatus 10 are a gas conduit system shown generally at 16, a water recirculating system shown generally at 18 and a liquid chemical recirculation system indicated generally at 20.

It is thus seen that the overall organization of the in stant invention includes the delivery of exhaust gases to a gas conduit system in which a cooling operation is conducted followed by an absorption and cleansing of impurities from the exhaust stream after which the exhaust stream is vented to the atmosphere. Gas conduit stream 16 includes an exhaust inlet 22 connected to exhaust outlet 12 of combustion chamber 14 at an angle approximately with the exhaust gases traveling into a main conduit 24 at a similar angle.

Main conduit 24 and exhaust inlet 22 are in fluid communication with a fresh air inlet 26 having an enlarged inlet opening 28 in which is mounted a blower shown generally at 30. Blower 39 includes a rotatable fan -32 mounted by apertured bracket 34 on inlet opening 23 and is driven by a motor 3d of any suitable type. Gas conduit system 16 also includes a downwardly inclined main conduit section 38 downstream of main conduit section 24. Downwardly inclined conduit 38 exits into chemical chamber 40, which also comprises a portion of chemical recirculating system 20, which is equipped with a substantially vertical vent stack 42 for delivering treated exhaust gases to the atmosphere.

In the operation of gas conduit system 16, motor 36 is driven to rotate fan 32 to induce fresh air into fresh air inlet 26. Exhaust gases from furnace 14 travel through exhaust outlet 12 into exhaust inlet 22 of gas conduit means 16. Because of the relative angles of exhaust inlet 22 and fresh air inlet 26, a slight pressure drop will be created at the junction of inlet 22 and main conduit 24 to allow for the efiicient operation of furnace 14. When the mixture of exhaust and clean gases enters main cond-uit 24, a cooling operation will be conducted, as more fully explained hereinafter. As the gas mixture enters downwardly inclined conduit 38, a cleaning step will be conducted which will be completed in tank 40 by the recovery of the liquid chemical with the processed exhaust gases exiting through vent stack 42 to the atmosphere.

Water recirculating system 18 includes a reservoir and cooler 44 of any conventional configuration that provides for the cooling of the liquids therein by ambient temperature. Cooler 44 is connected to a conventional pump 46, which is illustrated to be a centrifugal pump, but which may be of any suitable type, by an inlet conduit 43. Pump 46 delivers pressurized water from an outlet 50 to a header or manifold 52 having a plurality of branch conduits 54 in communication with the interior of main conduit 24. A plurality of shower heads 56 are in communication with branch pipes 54 to distribute water within main conduit 24 in a fine spray. Although shower heads 56 are illustrated as positioned along conduit 24 in a longitudinally spaced apart relation, it has been found that shower heads 56 may be spaced in any desired configuration, such as radially about conduit 24.

Positioned at the junction of main conduit 24 and downwardly inclined conduit 38 is a frusto-conical water outlet or drainage pipe 58 providing communication between the interior of conduits 24, 38 and a filter shown generally at 60. Filter 60 includes a closed receptacle 62 in which is placed a suitable filter material 64 such as activated charcoal or the like. Communicating between the bottom of filter receptacle 62 and a conventional pump 66 is a fluid conduit 68 which acts to deliver filtered liquids from filter 60 to pump 66. Pressurized fluid emitting from an outlet 68 of pump 66 is delivered through a con- U7 duit 70 to cooler or reservoir 44 after which the water recirculation cycle is repeated.

It will be seen that the injection of a finely divided water stream into main conduit 24 not only results in the cooling of exhaust gases emitting from furnace 14, but also performs an initial scrubbing operation because of the physical attraction between water droplets and smoke particles. Filter 60 effects the removal of much of the smoke particles entrained in the recirculating water. From time to time it is deemed advantageous to replace charcoal filter 64, which may be done without temporarily shutting down treatment apparatus by providing an alternative filter 60 connected to drainage pipe 58 and conduit 68 by a suitable manifold.

It should be apparent that the liquid emitting from filter 60 will be hot because of the exchange of heat occurring in conduit 24. The heated water will be considerably cooled in cooler 44 prior to recirculation. Despite the utilization of filter 60, the water recirculated within system 18 will become contaminated with smoke particles to an extent in derogation of the efficiency of the components of system 18. At such a time the recirculating fluid may be replaced by a suitable valve, not shown, downstream of pump 66.

An important feature of the instant invention resides in liquid chemical recirculating system 20 which includes a chemical reservoir tank 72 of a suitable size connected through a conduit 74 to a conventional pump 76; Pump 76 delivers a stream of high pressure chemicals through an outlet 78- to a conduit 80 having a plurality of branch lines 82 in fluid communication with the interior of downwardly extending conduit 38 of gas conduit means 16. Providing for the distribution of the pressurized chemical within conduit 38 are a plurality of shower heads 84 of similar type to shower heads 56, and which may be placed about conduit 38 in any suitable manner.

The cooled exhaust gases and inherently some of the coolant water will be received within conduit 38 and be subjected to cleaning by the chemical sprayed therein. The flowstream consisting of exhaust gases, fresh air, coolant water and the absorbent chemical will exist through a discharge opening 85 of conduit 38 to the interior of chemical chamber or tank 40. Since much of the sprayed chemical will be in the form of large droplets, a body of liquid 86 will accumulate in the bottom of tank 40. A plurality of baflles 88 are provided within tank 40 and are inclined toward the center of tank 40 to facilitate the condensation of the absorbent chemicals thereon and to deliver the condensed chemicals to the bottom of tank 40 in order. to minimize the loss of the absorbent chemical.

Positoned in the bottom of tank 40 is a bed of activated charcoal or other filter material 90 which acts to remove impurities from the absorbent chemical in a known manner. Communicating with filter material 90 through a screen or the like 92 is a chemical delivery conduit 94 in communication with a collecting reservoir 96. Providing communication between reservoir 96 and a conventional centrifugal pump 98 or the like is a fluid conduit 100. Pump 98 delivers pressurized chemical absorbent through a discharge conduit 102 to chemical tank 72.

In the operation of liquid chemical recirculating system 20, pump' 76 withdraws the chemical absorbent from tank 72 and injects it under pressure into conduit 82 after which'it is delivered into the interior of downwardly inclined conduit 38'of gas conduit system 16. The fine spray of chemical absorbent issuing from shower heads 84absorbs a substantial amount of the irritants in the exhaust stream coming from furnace 14. A considerable amount of the chemical absorbent is recovered by the gravitation of droplets into the bottom tank 40 and collects as a body of chemicals 86. A substantial amount of the chemical absorbent condenses on baflles 88 and subequently'falls into the bottom of tank 40. The fluids col- 1 lected in the bottom of tank 40 seep through charcoal filter into collecting reservoir 96. Pump 98 may operate continuously, or may preferably be actuated by a float valve in collecting reservoir 96, to deliver fluid into chemical tank 72 at which time the recirculation cycle is repeated.

While it is not completely understood at this time why the chemical solutions enumerated hereinafter act to remove combustion produced irritants from an exhaust stream, it is presently believed that a combined cleaning and absorption processis responsible. For example, cleansers other than sodium lauryl sulfate, borax and trisodium phosphate have been experimented with, none of which have produced acceptable results. While the use of either form of chlorophyll has proved feasible, the deletion thereof has resulted in an exhaust stream containing unacceptable amounts of combustion irritants.

The essential ingredients of the chemical absorbent and cleansing solution of the instant invention are (1) a sodium salt of a medium molecular weight synthetic ether sulfate of the formula where n is from ten to eighteen, (2) Na B O commonly known as borax, (3) chlorophyll of either the A or B type, (4) trisodium phosphate and (5)- a water carrier. One example of the chemical solution found to be eflicacious in the removal of combustion irritants from an exhaust stream is set forth in the following table:

Table I Component: Amount in parts by weight Sodium lauryl sulfate 16.0000 Borax (Na-2B407) 1.0000 Chlorophyll A .0023 Trisodium phosphate 4.5000 Water 78.4977

To prepare the chemical solution, an appropriate amount of each of the components may be acquired from a commercial source with the sodium lauryl sulfate being purchased under the trade name of Avirol Bod 183 from the Standard Chemical Corporation of Hoboken, NJ. Chlorophyll A is a well known chemical as indicated'in Merck Index, 7th Ed., 1960, p. 245. The Avirol Bod 183 should first be dispersed in half of the water. Borax and trisodium phosphate should be added to the balance of the water in the indicated amount with chlorophyll being added thereto as a concentrate. The two water solution portions are then stirred together until uniform.

Chemical tank 72 may then be filled with the prepared mixture with pump 76 being operated to deliver this mixture tothe interior of a downwardly inclined conduit 38.

Another example of the composition found eflicacious is set forth in the following table:

Table 11 This solution may be prepared-in substantially the same manner as the example of Table I. It should be pointed out that the first component appearing in Table II is the generalized form of sodium lauryl sulfate with the textbook formula thereof occurring when n is 12.

Still another example is set forth in the following table:

Table III Component: Amount in parts by weight Sodium lauryl sulfate 14.5000 Borax (Na B O 1.5000 Chlorophyll B .0422 Trisodium phosphate 4.0000 Water 79.9578

The solution of this example may be prepared in much the same manner as the two preceding examples. It should be pointed out that chlorophyll B is utilized but in a much greater amount than chlorophyll A is utilized in the preceding examples.

It is now seen that there is herein provided an improved exhaust gas treatment system having all of the advantages of this invention and others, including many advantages of great practical utility and commercial importance.

Since many embodiments may be made of the instant inventive concept, and since many modifications may be made in the embodiment hereinbefore shown and described, it is to be understood that the foregoing is to be interpreted merely as illustrative and not in a limiting sense.

I claim:

1. The process of treating an exhaust gas stream emitting from a combustion chamber including the steps of injecting water into said stream in a finely divided form for cooling said exhaust stream, injecting into said stream a chemical absorptive and cleansing material having an affinity for the irritant portions of an exhaust air stream and recovering a substantial quantity of the injected material and the irritant products contained therein, wherein the chemical material is composed of a minor portion consisting essentially of borax, chlorophyll, trisodium phosphate and where n is from 10 to 18 and a major portion consisting essentially of water.

2. The process of claim 1 wherein the chemical material consists essentially of 12 to 16 percent by weight 1.0 to 1.5 percent by weight borax, .0023 to .0422 percent by weight chlorophyll, 4.0 to 5.1 percent by weight trisodium phosphate, and water.

3. A system for treating exhaust gases comprising, in combination:

a substantially horizontal gas conduit;

exhaust gas inlet means at one end thereof;

fresh air inlet means at said end thereof;

spray means in said conduit for dispersing a liquid thereinto;

drainage means in communication with the other end of said conduit for recovering substantially all of said liquid from said conduit;

first recirculation system for circulating said liquid from said drainage means to said spray means;

a downwardly sloping conduit secured at one end in communication with the other end of the horizontal gas conduit for receiving gases therefrom;

second spray means in the last named conduit for dispersing a chemical cleaning liquid thereinto;

a chemical cleaning liquid receiving tank secured at the other end of the last named conduit for receiving gases and the chemical cleaning liquid therefrom;

an exhaust gas conduit communicating with said tank for removing gases therefrom; and

a second recirculation system for circulating the chemical cleaning liquid from the tank to the spray means.

4. The system of claim 3 further comprising:

a chemical cleaning liquid in said tank which consists essentially of water, borax, chlorophyll, trisodium phosphate and an alkali metal sulphate detergent.

5. The system of claim 4 wherein the chemical cleaning liquid consists essentially of:

a major portion of water; and

a minor portion consisting essentially of borax, chlorohyll, trisodium phosphate, and sodium n-laury] sulphate.

'6. The system of claim 3 further comprising:

a filter in the first recirculation system for removing particulate and dissolved matter from the liquid therein; and

a filter in the second recirculation system for removing particulate and dissolved matter from the chemical cleaning liquid.

7. The system of claim 6 further comprising:

cooling means in the first recirculation system.

8. The system of claim 3 wherein the chemical absorbent material consists essentially of a major portion of water and a minor portion of the combination of borax, chlorophyll, trisodium phosphate and an alkali sulphate detergent.

References Cited UNITED STATES PATENTS 2,090,466 8/1937 Bichowsky 55223 2,094,343 9/1937 Bichowsky 261--2 2,795,103 6/1957 Jenison -30 2,932,364 4/1960 Binter 6030 2,975,586 3/1961 Bray 6030 3,282,047 11/ 1966 Wertheimer 55--229 SAMIN N. ZAHARNA, Primary Examiner.

REUBEN FRIEDMAN, Examiner.

C. N. HART, Assistant Examiner. 

1. THE PROCESS OF TREATING AN EXHAUST GAS STREAM EMITTING FROM A COMBUSTION CHAMBER INCLUDING THE STEPS OF INJECTING WATER INTO SAID STREAM IN A FINELY DIVIDED FORM FOR COOLING SAID EXHAUST STREAM, INJECTING INTO SAID STREAM A CHEMICAL ABSORPTIVE AND CLEANSING MATERIAL HAVING AN AFFINITY FOR THE IRRITANT PORTIONS OF AN EXHAUST AIR STREAM AND RECOVERING A SUBSTANTIAL QUANTITY OF THE INJECTED MATERIAL AND THE IRRITANT PRODUCTS CONTAINED THEREIN, WHEREIN THE CHEMICAL MATERIAL IS COMPOSED OF A MINOR PORTION CON- 